Spider Ecology Research Articles

To pool or not to pool: Pooled metabarcoding does not affect estimates of prey diversity in spider gut content analysis

Abstract Gut content metabarcoding has provided important insights into the food web ecology of spiders, the most dominant terrestrial arthropod predators. In small invertebrates, like spiders, gut content analysis is often performed on whole body DNA extracts of individual predators, from which prey sequences are selectively enriched and sequenced. Since many spider species are generalist predators, large numbers of samples comprising individual spider specimens must be analysed to recover an exhaustive image of a spider species' prey spectrum, which is costly and time‐consuming. Pooled processing of bulk samples of multiple specimens has been suggested to reduce the necessary workload and cost while still recovering a representative estimate of the prey diversity. However, it is still unclear if pooling approaches lead to bias in recovering the prey spectrum and if the results are comparable with data from individually processed spiders. Here, we test the effects of metabarcoding pooled spider gut content on the recovered taxonomic diversity and composition of prey. Using a newly adapted primer pair, which efficiently enriches COI barcode sequences of diverse arthropod prey groups while suppressing spider amplification, we test if pooling leads to reduced taxonomic diversity or skewed estimates of prey composition. Our results show that pooling and individual processing recover highly correlated taxonomic diversity and composition of prey. The only exception are very rare prey items which were less well recovered by pooling. Our results support pooling as a cost‐effective and time‐efficient approach to recover the diet of generalist predators for population‐level studies of spider trophic interactions.

К 70-летию начала научной деятельности энтомолога и арахнолога Николая Борисовича Шлыкова

Karaganda Buketov University has been distinguished by highly professional scientific and pedagogical personnel since its formation. This was determined by the continuity of the creative potential of the Karaganda Pedagogical Institute. Nikolay Borisovich Shlykov the associate professor of the Faculty of Natural Sciences was among the generalists of the Pedagogical Institute. He was a brilliant professional biologist. He received practical training in the Entomology Laboratory of the Institute of Zoology of the Republic of Kazakhstan and became a first-class scientist and teacher. He developed entomological and arachnological research at the university. Shlykov was the first head of the Zoology Department of the Faculty of Natural Sciences of the Karaganda Pedagogical Institute from 1960 to 1965. At that time, he was engaged in the formation of new areas of scientific work, selected personnel and directed the development of fundamental zoological training courses. His scientific publications on the biology of poplar pests, fauna and ecology of spiders are relevant and valuable sources of information for modern scientists. The high level of quotability of N.B. Shlykov's data is the result of unique accuracy and content. This is a sample of research work for many generations of his students.

Spider Ecology and Behaviour—Spiders as Model Organisms

Spiders are versatile and ubiquitous generalist predators that can be found in all terrestrial ecosystems except for Antarctica [...].

Comment on Dunbar et al. (2022) “Webslinger vs. Dark Knight: First record of a false widow spider Steatoda nobilis preying on a pipistrelle bat in Britain”

Abstract. A recent publication in Ecosphere claimed to report the first case of a predation event by a theridiid spider on a bat globally and the first case of a member of the genus Steatoda preying on a mammal globally, and the paper concludes with possible implications for public health. Predation is typically understood to mean “capture, kill, and eat”. However, none of these aspects had been observed. Moreover, key aspects of bat biology were not taken into account, including that the bat in question was a flightless newborn, the capture of which would require some explanation. We revisit this interesting observation considering both bat and spider ecology.

Tangled in a Web: Management Type and Vegetation Shape the Occurrence of Web-Building Spiders in Protected Areas.

Land management of parks and vegetation complexity can affect arthropod diversity and subsequently alter trophic interactions between predators and their prey. In this study, we examined spiders in five parks with varying management histories and intensities to determine whether certain spider species were associated with particular plants. We also determined whether web architecture influenced spider occurrence. Our results showed that humpbacked orb-weavers (Eustala anastera) were associated with an invasive plant, Chinese privet (Ligustrum sinense). This study revealed how invasive plants can potentially influence certain spider communities, as evidenced by this native spider species only occurring on invasive plants. Knowing more about spider populations-including species makeup and plants they populate-will give insights into how spider populations are dealing with various ecosystem changes. While we did not assess the effect of invasive plants on the behavior of spiders, it is possible that invasive species may not always be harmful to ecosystems; in the case of spiders, invasive plants may serve as a useful environment to live in. More studies are needed to ascertain whether invasive plants can have adverse effects on spider ecology in the long term.

Review of Spider Ecology During Carrion Decomposition, with a Field Study on Density and Taxa Richness in Pitfall Trap Captures of Geophilic Spiders (Aranea: Anyphaenidae, Corinnidae, Linyphiidae, Lycosidae, Salticidae)

AbstractDuring a recent pig carrion succession study in northwest Florida, United States, we noticed an abundance of spiders but found that literature on spider ecology at carrion is sparse and scattered. We compiled a literature review of 569 carrion succession studies, of which 37 studies specifically mentioned the presence of spiders, with less than a third providing species-level identifications and only half providing family-level identifications. Nineteen spider families have been reported at carrion in the literature. Spiders are recognized as generalist, opportunistic predators in carrion succession studies, but only 38% of the studies that mentioned spiders during carrion succession included any ecological information. Data on spiders in the present experiment were compared to background samples, finding that the difference in abundance was statistically significant for all spider species combined. Seven species of spiders from five families were identified from both background and carrion succession samples; statistical differences in abundance were found for three species: the linyphiid Florinda coccinea and the lycosids Tigrosa annexa and Pirata seminolus. The family Corinnidae is reported from carrion for the first time. This research reviews the existing literature on spider ecology during carrion succession, provides additional data on species identity and abundance, and demonstrates the potential significance of spiders in carrion ecology and forensic investigations.

The Evolution of Dragline Initiation in Spiders: Multiple Transitions from Multi- to Single-Gland Usage

Despite the recognition of spider silk as a biological super-material and its dominant role in various aspects of a spider’s life, knowledge on silk use and silk properties is incomplete. This is a major impediment for the general understanding of spider ecology, spider silk evolution and biomaterial prospecting. In particular, the biological role of different types of silk glands is largely unexplored. Here, I report the results from a comparative study of spinneret usage during silk anchor and dragline spinning. I found that the use of both anterior lateral spinnerets (ALS) and posterior median spinnerets (PMS) is the plesiomorphic state of silk anchor and dragline spinning in the Araneomorphae, with transitions to ALS-only use in the Araneoidea and some smaller lineages scattered across the spider tree of life. Opposing the reduction to using a single spinneret pair, few taxa have switched to using all ALS, PMS and the posterior lateral spinnerets (PLS) for silk anchor and dragline formation. Silk fibres from the used spinnerets (major ampullate, minor ampullate and aciniform silk) were generally bundled in draglines after the completion of silk anchor spinning. Araneoid spiders were highly distinct from most other spiders in their draglines, being composed of major ampullate silk only. This indicates that major ampullate silk properties reported from comparative measurements of draglines should be handled with care. These observations call for a closer investigation of the function of different silk glands in spiders.

Spatiotemporal Variation in House Spider Phenology at a National Scale Using Citizen Science

The seasonal appearance of Tegenaria and Eratigena (the best known of the UK genera termed house spiders) results in considerable public and media interest. Here, we present the largest dataset ever gathered on the occurrence of house spiders anywhere in the world. We collected almost 10,000 records from different locations within the UK (amounting to ∼250× more locations and 25× more records than any previous study) over a six-month period. Using this dataset, which contained details of sighting dates, times, location within UK, location within the home, location within rooms, and sex, we were able to investigate a number of aspects of house spider ecology. Eightytwo percent of records were males, supporting previous studies that showed house spider surges in autumn are predominantly males seeking mates. Sightings peaked in mid-September with a significant northwest progression across the UK as autumn progressed. Daily activity peaked at 19.35 hrs and spiders were seen more or less uniformly throughout different rooms; we discuss why this is more likely to be due to spider ecology than human behaviour. Within rooms, there was a sex-based difference in ecology with females more common on ceilings and doors/windows and males more common on walls, possibly because of sex-specific differences in mobility.

An estimated 400\u2013800 million tons of prey are annually killed by the global spider community

Spiders have been suspected to be one of the most important groups of natural enemies of insects worldwide. To document the impact of the global spider community as insect predators, we present estimates of the biomass of annually killed insect prey. Our estimates assessed with two different methods suggest that the annual prey kill of the global spider community is in the range of 400–800 million metric tons (fresh weight), with insects and collembolans composing >90% of the captured prey. This equals approximately 1‰ of the global terrestrial net primary production. Spiders associated with forests and grasslands account for >95% of the annual prey kill of the global spider community, whereas spiders in other habitats are rather insignificant contributors over a full year. The spider communities associated with annual crops contribute less than 2% to the global annual prey kill. This, however, can be partly explained by the fact that annual crop fields are “disturbed habitats” with a low buildup of spider biomass and that agrobiont spiders often only kill prey over short time periods in a year. Our estimates are supported by the published results of exclusion experiments, showing that the number of herbivorous/detritivorous insects and collembolans increased significantly after spider removal from experimental plots. The presented estimates of the global annual prey kill and the relative contribution of spider predation in different biomes improve the general understanding of spider ecology and provide a first assessment of the global impact of this very important predator group.

Material properties of evolutionary diverse spider silks described by variation in a single structural parameter.

Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, this variation is shown here to be confined to evolutionary shifts along a single universal performance trajectory. This reveals an underlying design principle that is maintained across large changes in both spider ecology and silk chemistry. Persistence of this design principle becomes apparent after the material properties are defined relative to the true alignment parameter, which describes the orientation and stretching of the protein chains in the silk fiber. Our results show that the mechanical behavior of all Entelegynae major ampullate silk fibers, under any conditions, are described by this single parameter that connects the sequential action of three deformation micromechanisms during stretching: stressing of protein-protein hydrogen bonds, rotation of the β-nanocrystals and growth of the ordered fraction. Conservation of these traits for over 230 million years is an indication of the optimal design of the material and gives valuable clues for the production of biomimetic counterparts based on major ampullate spider silk.

Functional anatomy of the pretarsus in whip spiders (Arachnida, Amblypygi)

Whip spiders (Amblypygi) are a small, cryptic order of arachnids mainly distributed in the tropics. Some basal lineages (families Charinidae and Charontidae) have adhesive pads on the tips of their six walking legs. The present study describes the macro- and ultrastructure of these pads and investigates their contact mechanics and adhesive strength on smooth and rough substrates. Furthermore, the structure of the pretarsus and its kinematics are compared in Charon cf. grayi (with an adhesive pad) and Phrynus longipes (without an adhesive pad). The adhesive pads exhibit an elaborate structure with a unique combination of structural features of smooth and hairy foot pads including a long transversal contact zone performing lateral detachment, a thick internally-branched cuticle with longitudinal ribs and hexagonal surface microstructures with spatulate keels. The contact area of the pads on smooth glass is discontinuous due to the spatulate microstructures with a discontinuous detachment, which could be observed in vivo by high speed videography at a rate of up to 10,000 fps. Adhesive strength was measured with vertical whole animal pull-off tests, obtaining mean values between 55 and 200 kPa. The occurrence of viscous lipid secretions between microstructures was occasionally observed, which, however, seems not to be a necessity for good foothold. The results are discussed in relation to the whip spider's ecology and evolution. Structure–function relationships of the adhesive pads are compared to those of insects and vertebrates.

More than a safety line: jump-stabilizing silk of salticids

Salticids are diurnal hunters known for acute vision, remarkable predatory strategies and jumping ability. Like other jumpers, they strive for stability and smooth landings. Instead of using inertia from swinging appendages or aerodynamic forces by flapping wings as in other organisms, we show that salticids use a different mechanism for in-air stability by using dragline silk, which was previously believed to function solely as a safety line. Analyses from high-speed images of jumps by the salticid Hasarius adansoni demonstrate that despite being subject to rearward pitch at take-off, spiders with dragline silk can change body orientation in the air. Instantaneous drag and silk forces calculated from kinematic data further suggest a comparable contribution to deceleration and energy dissipation, and reveal that adjustments by the spider to the silk force can reverse its body pitch for a predictable and optimal landing. Without silk, upright-landing spiders would slip or even tumble, deferring completion of landing. Thus, for salticids, dragline silk is critical for dynamic stability and prey-capture efficiency. The dynamic functioning of dragline silk revealed in this study can advance the understanding of silk's physiological control over material properties and its significance to spider ecology and evolution, and also provide inspiration for future manoeuvrable robot designs.

Plasticity in major ampullate silk production in relation to spider phylogeny and ecology.

Spider major ampullate silk is a high-performance biomaterial that has received much attention. However, most studies ignore plasticity in silk properties. A better understanding of silk plasticity could clarify the relative importance of chemical composition versus processing of silk dope for silk properties. It could also provide insight into how control of silk properties relates to spider ecology and silk uses.We compared silk plasticity (defined as variation in the properties of silk spun by a spider under different conditions) between three spider clades in relation to their anatomy and silk biochemistry. We found that silk plasticity exists in RTA clade and orbicularian spiders, two clades that differ in their silk biochemistry. Orbiculariae seem less dependent on external spinning conditions. They probably use a valve in their spinning duct to control friction forces and speed during spinning. Our results suggest that plasticity results from different processing of the silk dope in the spinning duct. Orbicularian spiders seem to display better control of silk properties, perhaps in relation to their more complex spinning duct valve.

Arboreal Spider Ecology on Saltcedar (Tamarix) at Big Spring, Howard County, Texas

The arboreal species of spiders on saltcedar, Tamarix spp., at Big Spring, Howard County, TX, were surveyed to determine which species could pose a threat to the success of the biological control agent Diorhabda elongata (Brulle) (Coleoptera: Chrysomelidae). This resulted in a list of the spider genera and species found on tamarisk and some initial information on spider ecology in association with this weed tree. Of the 1,495 specimens of spiders collected above ground level during the 3 years of study at the site, 55 spider species in 15 families were found on saltcedar trees. The most abundant species of spiders were mapped to determine their habitat on the trees and in relation to other species. Orb-weavers (Araneidae) and jumping spiders (Salticidae) were the most diverse families, as well as being common, but mesh web-weavers (Dictynidae), while less diverse, were individually numerous. Only orb-weavers were observed to feed on D. elongata in the field.

THE EMERGENCE OF MANIPULATIVE EXPERIMENTS IN ECOLOGICAL SPIDER RESEARCH (1684–1973)

Abstract The history of spider ecology is discussed from its early beginnings in 1684 when the natural historian Martin Lister published his observations, to the post-war period up until 1973 when ecological spider research gathered momentum. While there have been many important observations since Lister, spider ecology appeared explicitly in the titles of papers only after the turn of the 20th century. However, much of what was published up until the 1950s is of little scientific value because these works contained natural history notes and conjecture, not manipulative experimentation. The exception was a paper written in 1939 by Pontus Palmgren who was not an ecologist but paradoxically a functional anatomist with a particular interest in ornithology. His paper was in the spirit of Ernst Haeckel's original definition of ecology that was seen as synonymous with physiology, a legacy that was detected in many of the papers decades after Palmgren. However, there was little evidence that ecological theory wa...

Constraining Webs

Spiderwebs and Silk Tracing Evolution from Molecules to Genes to Phenotypes. by Catherine L. Craig. Oxford University Press, New York, 2003. 256 pp. $59.95, £40. ISBN 0-19-512916-4. Weaving together findings from biochemistry, molecular genetics, cellular physiology, ecology, and behavior, Craig explores the links between the molecular evolution of silk proteins and the evolution, diversity, and ecology of spiders.

Spiders (Araneae) useful for pest limitation and bioindication

In northern Europe at least, extensive knowledge of the systematics and ecology of spiders leads the authors to consider them as a very suitable group for pest limitation and for biodiagnostic purposes. An examination of both the qualitative and quantitative aspects of perdition by spider populations and communities is discussed as well as the evolution of some human factors occurring in agroecosystems that are likely to induce changes in spider predation such as chemical spraying and cultural practices. Studies addressing the recolonisation of agroecosystems by spiders, taking into account their dispersing abilities and habitat selection are summarised, followed by a discussion of the global efficiency of spiders as predators in such environments, the risks associated with their use and how to maximise their efficiency. The bioindicative value of spiders is presented by referring successively to population level and community level. The growth rate or the reproductive rate observed in natural populations can be correlated with the amount of prey ingested in the field. Thus, these parameters give an indirect estimation of the habitat quality. Two specific field experiments are presented to illustrate this ecological concept. Moreover, the role of spiders as indicators of heavy metal pollution (atmospheric or soil pollution) integrated by organisms living close to sources of pollution is discussed by reference to a set of laboratory and field experiments. Due to the close correspondence between the vegetation architecture and the composition of the associated spider community, it is argued (with a list of examples) that fluctuations in the spider community structure allows the bioevaluation of human disturbances. Based on the composition of the spider communities, methods of ecological classifications of natural habitats in several European countries are presented.

Spider Ecology

EcologyVolume 75, Issue 5 p. 1523-1524 Article Spider Ecology Ann L. Rypstra, Ann L. RypstraSearch for more papers by this author Ann L. Rypstra, Ann L. RypstraSearch for more papers by this author First published: 01 July 1994 https://doi.org/10.2307/1937483AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume75, Issue5July 1994Pages 1523-1524 RelatedInformation

Aerial web-weaving spiders: Linking molecular and organismal processes in evolution

Aerial web-weaving spiders display a wide variety of foraging behaviors that can be tied to the evolution of one family of proteins, the silks. In some cases, the physical structure and mechanical properties of silks alone determine the ecology of spiders: the habitats in which they forage, the prey they capture and their subsequent reproductive success. Future studies that integrate research on the physical structure of silks, the molecular genetics of silk synthesis and the foraging ecology of spiders in primitive and derived phylogenetic groups could reveal how molecular and organismal processes interact in evolution.

Ecology of spiders inhabiting abandoned mammal burrows in South African savanna.

In the Nylsvley Nature Reserve, in the South African savanna, the spider community in 320 abandoned mammal burrows was investigated. Three species, Agelena ocellata (Agelenidae), Euprosthenops proximus (Pisauridae) and Smeringopus pallidus (Pholcidae), coexisted in the burrows. The number of individuals and the number of species inhabiting the burrows increased with burrow size. Gerbil burrows were apparently too small to provide space for more than one individual of any of the three species. Only the burrows of springhares, warthogs, and antbears contained more than one spider. When artificial burrows were provided a rapid increase in settlement resulted. Competition for space therefore seems to be the determining factor influencing the population size. A relatively low number of prey items (136, in 119 webs) were found in agelenid webs only. Kleptoparasitic ants were observed stealing prey items from the webs.